Interest in flame retardant fibrous materials steadily has increased over the past decade spurred in part by a recognition of the serious hazards fires pose to property and life. New and stricter fire safety standards are being proposed by both governmental and non-governmental sources. The National Fire Protection Association estimates that in 1970 more than 2.5 million fires caused $2.6 billion in direct property losses and another $7.8 billion in indirect losses. Nearly 2 million people are involved in fires each year, and of these about 75,000 are hospitalized. Fires associated with flammable fabrics alone are estimated to cause 200,000 to 300,000 injuries each year. Associated medical costs are staggering, running well into the hundreds of millions of dollars. Accordingly a number of inherently non-burning fibrous materials have been proposed to offer the public a greater degree of fire safety particularly when fibrous articles are required for use in fire-critical environments, e.g., children's sleepwear, suits for firefighters, hospital furnishings, uniforms for military and civilian flight personnel, etc.
For instance, aromatic polyester flame retardant fibrous materials of the recurring structural formula: ##SPC1##
Where X is chlorine or bromine, Y is hydrogen, chlorine, or bromine, R and R' may be the same or different and represent lower alkyl groups, hydrogen, or together constitute a cyclic hydrocarbon group, and n - at least 25, offer a significant degree of fire safety. A minor concentration of an oxide of antimony optionally may be dispersed within the same. It has been found, however, that such fibrous materials tend to possess a relatively high glass transition temperature, and to be highly resistant to dyeing by the usual techniques for applying a disperse dye even if a usual dye carrier is employed. It further has been observed that common dye carriers such as o-phenylphenol, biphenyl, butyl benzoate, toluene, benzene, methyl salicylate, naphthalene, etc. tend to degrade fibrous materials of such halogenated aromatic polyesters. For instance, the fibrous material may exhibit any or all of the following: coalescence, stiffness, a lessened strength, broken fils, and dullness.
It is an object of the present invention to provide an improved process for the dyeing of certain halogenated aromatic polyester fibrous materials.
It is an object of the present invention to provide an improved process wherein certain halogenated aromatic polyester fibrous materials are effectively dyed with disperse dyes.
It is another object of the present invention to provide an improved dyeing process for certain halogenated aromatic polyester fibrous materials which can be carried out in the substantial absence of the usual fiber degradation commonly encountered with such fibrous materials.
These and other objects, as well as the scope, nature, and utilization of the claimed invention will be apparent to those skilled in the art from the following detailed description and appended claims.